The very thought that a man could do it to his own family is horrific. And yet we know there are people like that. Twisted and cruel, without respect for the true dignity of human life. Such men deserve to be punished, and many think that only the ultimate punishment of death is fitting when evidence of the horror is so plain.

What could really go through a man’s head as he takes charcoal starter fluid and spreads it within his home? Spreads it especially near his children’s bedroom and near the front door so that when he ignites it it will be that much more difficult to rescue the children being burned alive inside?

There was no one with Cameron Todd Willingham in his home to see him spreading the starter fluid, but there was evidence that he had done so, and this evidence was considered at his trial. Char patterns on the floor in multiple spots in the shape of puddles. Melting of the aluminum threshold at the front door that was a morbid reminder of the extreme heat generated. The presence of crazed glass that confirmed the extreme heat of the fire. All of these were things that arson science said were characteristics of fires started deliberately with the use of accelerants.

The science just happened to be wrong.

Although the National Fire Protection Association published a seminal report as early as 1992 that dispelled much of what had been thought to be understood about the science of arson detection, it has taken many years for those conclusions to become accepted. The fact is, though, that many of the earmarks that arson investigators confidently believed to be conclusive evidence of arson are, in fact, also caused from accidental fires.

Willingham was convicted of murder and executed by lethal injection by the State of Texas on February 17, 2004. Last year, the New Yorker published an article by David Grann that examined the evidence in light of modern understanding of arson science, concluding that there was no evidence for arson that can be sustained under modern critical examination. His full article can be read here.

To be sure, there was other evidence considered at Willingham’s trial in addition to the forensic arson evidence that pointed to his guilt, but the conclusions of the arson investigators were a substantial factor in his conviction. So much so that the modern understanding of what was found at his home is undeniably sufficient to raise a “reasonable doubt” whether he was guilty of the crime for which he was executed.

Many are concerned that this case is just a hint of a gross injustice that has been inflicted on many men. Flawed arson science has been applied in at least hundreds of cases and probably thousands of cases so that it seems likely at least some of those convicted were, in fact, innocent.

In discussions about the legitimacy of the capital punishment, one of the arguments that those opposed frequently make is that the death penalty is final; there is no way to correct an error if it is later discovered and at least restore a portion of life to the person convicted. This argument is very often dismissed. Surely, the counter-argument goes, there are cases where the evidence is so strong that there can be no doubt at all the person is guilty. Those are the cases in which it should be applied, proponents say. After all, those accused are given many, many opportunities to refute the evidence against them, so much so that the appeals of their convictions routinely take a decade or more. Indeed, in the case of Kansas v. Marsh in 2006, Justice Scalia dismissed criticism of the death penalty in the United States as coming from “sanctimonious … finger-waggers” and suggests that there has not in recent years been “a single case — not one — in which it is clear that a person was executed for a crime he did not commit.”

But there was that level of certainty in the Willingham case, seemingly backed by the best scientific understanding of those who examined the evidence. And still the conclusion seems to have been wrong. Last month, the Texas Forensic Science Commission acknowledged in a preliminary report that there were flaws in the arson evidence that was used in the case. But the controversy has not ended. The Commission’s founding chairman, Samuel Bassett, was removed from that position in an abrupt move by the governor of Texas, Rick Perry. In a memorandum to the Commission publicized in the last few days, Bassett has urged that the investigation into flawed arson science be expanded: How long has such flawed science been applied? Did the Fire Marshall’s Office wait too long in adopting more modern scientific standards?

These are not questions whose answers we should fear. Indeed, answering them is critical to moving forwards in a positive way.